Catheter imaging technology has long been recognized for its potential use in medical applications that involve visualizing the structure and conditions of a body. For example, catheter imaging technology may be used to locate anatomy, position diagnostic and therapeutic medical devices, and monitor surgery and surgical results.
Existing catheter imaging techniques include optical coherence domain reflectometers (OCDR), optical coherence tomography (OCT), acoustic imaging, intravascular ultrasound (IVUS), and optical triangulation.
Examples of utilizing OCDR to perform optical imaging are described in U.S. Pat. Nos. 5,459,570 and 5,321,501, both issued to Swanson et al., which are hereby incorporated by reference in their entirety.
An example of utilizing acoustic imaging is described in U.S. Pat. No. 4,951,677, issued to Crowley et al., which is hereby incorporated by reference.
Generally, these techniques involve emitting energy, such as light or sound, directed at a particular object and then detecting the energy's reflection or echo. Those skilled in the art will appreciate, however, that when using the techniques that emit high-frequency energy, such as near-infrared light or high-frequency ultrasound, in a body, blood may present a problem. This is due primarily to the presence of erythrocytes, or red blood cells (RBCs). The RBCs are of the size that interfere with short waves such as those of the high frequency energy. For example, in the case of OCT, blood may cause optical attenuation due to absorption and scattering.
In view of these limitations of conventional imaging catheters, an improved imaging device is needed.